1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/third_party/libevent/evthread.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,445 @@
1.4 +/*
1.5 + * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + * 1. Redistributions of source code must retain the above copyright
1.11 + * notice, this list of conditions and the following disclaimer.
1.12 + * 2. Redistributions in binary form must reproduce the above copyright
1.13 + * notice, this list of conditions and the following disclaimer in the
1.14 + * documentation and/or other materials provided with the distribution.
1.15 + * 3. The name of the author may not be used to endorse or promote products
1.16 + * derived from this software without specific prior written permission.
1.17 + *
1.18 + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.19 + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.20 + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.21 + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.22 + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.23 + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.24 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.25 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.26 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.27 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.28 + */
1.29 +
1.30 +#include "event2/event-config.h"
1.31 +
1.32 +#ifndef _EVENT_DISABLE_THREAD_SUPPORT
1.33 +
1.34 +#include "event2/thread.h"
1.35 +
1.36 +#include <stdlib.h>
1.37 +#include <string.h>
1.38 +
1.39 +#include "log-internal.h"
1.40 +#include "mm-internal.h"
1.41 +#include "util-internal.h"
1.42 +#include "evthread-internal.h"
1.43 +
1.44 +#ifdef EVTHREAD_EXPOSE_STRUCTS
1.45 +#define GLOBAL
1.46 +#else
1.47 +#define GLOBAL static
1.48 +#endif
1.49 +
1.50 +/* globals */
1.51 +GLOBAL int _evthread_lock_debugging_enabled = 0;
1.52 +GLOBAL struct evthread_lock_callbacks _evthread_lock_fns = {
1.53 + 0, 0, NULL, NULL, NULL, NULL
1.54 +};
1.55 +GLOBAL unsigned long (*_evthread_id_fn)(void) = NULL;
1.56 +GLOBAL struct evthread_condition_callbacks _evthread_cond_fns = {
1.57 + 0, NULL, NULL, NULL, NULL
1.58 +};
1.59 +
1.60 +/* Used for debugging */
1.61 +static struct evthread_lock_callbacks _original_lock_fns = {
1.62 + 0, 0, NULL, NULL, NULL, NULL
1.63 +};
1.64 +static struct evthread_condition_callbacks _original_cond_fns = {
1.65 + 0, NULL, NULL, NULL, NULL
1.66 +};
1.67 +
1.68 +void
1.69 +evthread_set_id_callback(unsigned long (*id_fn)(void))
1.70 +{
1.71 + _evthread_id_fn = id_fn;
1.72 +}
1.73 +
1.74 +int
1.75 +evthread_set_lock_callbacks(const struct evthread_lock_callbacks *cbs)
1.76 +{
1.77 + struct evthread_lock_callbacks *target =
1.78 + _evthread_lock_debugging_enabled
1.79 + ? &_original_lock_fns : &_evthread_lock_fns;
1.80 +
1.81 + if (!cbs) {
1.82 + if (target->alloc)
1.83 + event_warnx("Trying to disable lock functions after "
1.84 + "they have been set up will probaby not work.");
1.85 + memset(target, 0, sizeof(_evthread_lock_fns));
1.86 + return 0;
1.87 + }
1.88 + if (target->alloc) {
1.89 + /* Uh oh; we already had locking callbacks set up.*/
1.90 + if (target->lock_api_version == cbs->lock_api_version &&
1.91 + target->supported_locktypes == cbs->supported_locktypes &&
1.92 + target->alloc == cbs->alloc &&
1.93 + target->free == cbs->free &&
1.94 + target->lock == cbs->lock &&
1.95 + target->unlock == cbs->unlock) {
1.96 + /* no change -- allow this. */
1.97 + return 0;
1.98 + }
1.99 + event_warnx("Can't change lock callbacks once they have been "
1.100 + "initialized.");
1.101 + return -1;
1.102 + }
1.103 + if (cbs->alloc && cbs->free && cbs->lock && cbs->unlock) {
1.104 + memcpy(target, cbs, sizeof(_evthread_lock_fns));
1.105 + return event_global_setup_locks_(1);
1.106 + } else {
1.107 + return -1;
1.108 + }
1.109 +}
1.110 +
1.111 +int
1.112 +evthread_set_condition_callbacks(const struct evthread_condition_callbacks *cbs)
1.113 +{
1.114 + struct evthread_condition_callbacks *target =
1.115 + _evthread_lock_debugging_enabled
1.116 + ? &_original_cond_fns : &_evthread_cond_fns;
1.117 +
1.118 + if (!cbs) {
1.119 + if (target->alloc_condition)
1.120 + event_warnx("Trying to disable condition functions "
1.121 + "after they have been set up will probaby not "
1.122 + "work.");
1.123 + memset(target, 0, sizeof(_evthread_cond_fns));
1.124 + return 0;
1.125 + }
1.126 + if (target->alloc_condition) {
1.127 + /* Uh oh; we already had condition callbacks set up.*/
1.128 + if (target->condition_api_version == cbs->condition_api_version &&
1.129 + target->alloc_condition == cbs->alloc_condition &&
1.130 + target->free_condition == cbs->free_condition &&
1.131 + target->signal_condition == cbs->signal_condition &&
1.132 + target->wait_condition == cbs->wait_condition) {
1.133 + /* no change -- allow this. */
1.134 + return 0;
1.135 + }
1.136 + event_warnx("Can't change condition callbacks once they "
1.137 + "have been initialized.");
1.138 + return -1;
1.139 + }
1.140 + if (cbs->alloc_condition && cbs->free_condition &&
1.141 + cbs->signal_condition && cbs->wait_condition) {
1.142 + memcpy(target, cbs, sizeof(_evthread_cond_fns));
1.143 + }
1.144 + if (_evthread_lock_debugging_enabled) {
1.145 + _evthread_cond_fns.alloc_condition = cbs->alloc_condition;
1.146 + _evthread_cond_fns.free_condition = cbs->free_condition;
1.147 + _evthread_cond_fns.signal_condition = cbs->signal_condition;
1.148 + }
1.149 + return 0;
1.150 +}
1.151 +
1.152 +struct debug_lock {
1.153 + unsigned locktype;
1.154 + unsigned long held_by;
1.155 + /* XXXX if we ever use read-write locks, we will need a separate
1.156 + * lock to protect count. */
1.157 + int count;
1.158 + void *lock;
1.159 +};
1.160 +
1.161 +static void *
1.162 +debug_lock_alloc(unsigned locktype)
1.163 +{
1.164 + struct debug_lock *result = mm_malloc(sizeof(struct debug_lock));
1.165 + if (!result)
1.166 + return NULL;
1.167 + if (_original_lock_fns.alloc) {
1.168 + if (!(result->lock = _original_lock_fns.alloc(
1.169 + locktype|EVTHREAD_LOCKTYPE_RECURSIVE))) {
1.170 + mm_free(result);
1.171 + return NULL;
1.172 + }
1.173 + } else {
1.174 + result->lock = NULL;
1.175 + }
1.176 + result->locktype = locktype;
1.177 + result->count = 0;
1.178 + result->held_by = 0;
1.179 + return result;
1.180 +}
1.181 +
1.182 +static void
1.183 +debug_lock_free(void *lock_, unsigned locktype)
1.184 +{
1.185 + struct debug_lock *lock = lock_;
1.186 + EVUTIL_ASSERT(lock->count == 0);
1.187 + EVUTIL_ASSERT(locktype == lock->locktype);
1.188 + if (_original_lock_fns.free) {
1.189 + _original_lock_fns.free(lock->lock,
1.190 + lock->locktype|EVTHREAD_LOCKTYPE_RECURSIVE);
1.191 + }
1.192 + lock->lock = NULL;
1.193 + lock->count = -100;
1.194 + mm_free(lock);
1.195 +}
1.196 +
1.197 +static void
1.198 +evthread_debug_lock_mark_locked(unsigned mode, struct debug_lock *lock)
1.199 +{
1.200 + ++lock->count;
1.201 + if (!(lock->locktype & EVTHREAD_LOCKTYPE_RECURSIVE))
1.202 + EVUTIL_ASSERT(lock->count == 1);
1.203 + if (_evthread_id_fn) {
1.204 + unsigned long me;
1.205 + me = _evthread_id_fn();
1.206 + if (lock->count > 1)
1.207 + EVUTIL_ASSERT(lock->held_by == me);
1.208 + lock->held_by = me;
1.209 + }
1.210 +}
1.211 +
1.212 +static int
1.213 +debug_lock_lock(unsigned mode, void *lock_)
1.214 +{
1.215 + struct debug_lock *lock = lock_;
1.216 + int res = 0;
1.217 + if (lock->locktype & EVTHREAD_LOCKTYPE_READWRITE)
1.218 + EVUTIL_ASSERT(mode & (EVTHREAD_READ|EVTHREAD_WRITE));
1.219 + else
1.220 + EVUTIL_ASSERT((mode & (EVTHREAD_READ|EVTHREAD_WRITE)) == 0);
1.221 + if (_original_lock_fns.lock)
1.222 + res = _original_lock_fns.lock(mode, lock->lock);
1.223 + if (!res) {
1.224 + evthread_debug_lock_mark_locked(mode, lock);
1.225 + }
1.226 + return res;
1.227 +}
1.228 +
1.229 +static void
1.230 +evthread_debug_lock_mark_unlocked(unsigned mode, struct debug_lock *lock)
1.231 +{
1.232 + if (lock->locktype & EVTHREAD_LOCKTYPE_READWRITE)
1.233 + EVUTIL_ASSERT(mode & (EVTHREAD_READ|EVTHREAD_WRITE));
1.234 + else
1.235 + EVUTIL_ASSERT((mode & (EVTHREAD_READ|EVTHREAD_WRITE)) == 0);
1.236 + if (_evthread_id_fn) {
1.237 + EVUTIL_ASSERT(lock->held_by == _evthread_id_fn());
1.238 + if (lock->count == 1)
1.239 + lock->held_by = 0;
1.240 + }
1.241 + --lock->count;
1.242 + EVUTIL_ASSERT(lock->count >= 0);
1.243 +}
1.244 +
1.245 +static int
1.246 +debug_lock_unlock(unsigned mode, void *lock_)
1.247 +{
1.248 + struct debug_lock *lock = lock_;
1.249 + int res = 0;
1.250 + evthread_debug_lock_mark_unlocked(mode, lock);
1.251 + if (_original_lock_fns.unlock)
1.252 + res = _original_lock_fns.unlock(mode, lock->lock);
1.253 + return res;
1.254 +}
1.255 +
1.256 +static int
1.257 +debug_cond_wait(void *_cond, void *_lock, const struct timeval *tv)
1.258 +{
1.259 + int r;
1.260 + struct debug_lock *lock = _lock;
1.261 + EVUTIL_ASSERT(lock);
1.262 + EVLOCK_ASSERT_LOCKED(_lock);
1.263 + evthread_debug_lock_mark_unlocked(0, lock);
1.264 + r = _original_cond_fns.wait_condition(_cond, lock->lock, tv);
1.265 + evthread_debug_lock_mark_locked(0, lock);
1.266 + return r;
1.267 +}
1.268 +
1.269 +void
1.270 +evthread_enable_lock_debuging(void)
1.271 +{
1.272 + struct evthread_lock_callbacks cbs = {
1.273 + EVTHREAD_LOCK_API_VERSION,
1.274 + EVTHREAD_LOCKTYPE_RECURSIVE,
1.275 + debug_lock_alloc,
1.276 + debug_lock_free,
1.277 + debug_lock_lock,
1.278 + debug_lock_unlock
1.279 + };
1.280 + if (_evthread_lock_debugging_enabled)
1.281 + return;
1.282 + memcpy(&_original_lock_fns, &_evthread_lock_fns,
1.283 + sizeof(struct evthread_lock_callbacks));
1.284 + memcpy(&_evthread_lock_fns, &cbs,
1.285 + sizeof(struct evthread_lock_callbacks));
1.286 +
1.287 + memcpy(&_original_cond_fns, &_evthread_cond_fns,
1.288 + sizeof(struct evthread_condition_callbacks));
1.289 + _evthread_cond_fns.wait_condition = debug_cond_wait;
1.290 + _evthread_lock_debugging_enabled = 1;
1.291 +
1.292 + /* XXX return value should get checked. */
1.293 + event_global_setup_locks_(0);
1.294 +}
1.295 +
1.296 +int
1.297 +_evthread_is_debug_lock_held(void *lock_)
1.298 +{
1.299 + struct debug_lock *lock = lock_;
1.300 + if (! lock->count)
1.301 + return 0;
1.302 + if (_evthread_id_fn) {
1.303 + unsigned long me = _evthread_id_fn();
1.304 + if (lock->held_by != me)
1.305 + return 0;
1.306 + }
1.307 + return 1;
1.308 +}
1.309 +
1.310 +void *
1.311 +_evthread_debug_get_real_lock(void *lock_)
1.312 +{
1.313 + struct debug_lock *lock = lock_;
1.314 + return lock->lock;
1.315 +}
1.316 +
1.317 +void *
1.318 +evthread_setup_global_lock_(void *lock_, unsigned locktype, int enable_locks)
1.319 +{
1.320 + /* there are four cases here:
1.321 + 1) we're turning on debugging; locking is not on.
1.322 + 2) we're turning on debugging; locking is on.
1.323 + 3) we're turning on locking; debugging is not on.
1.324 + 4) we're turning on locking; debugging is on. */
1.325 +
1.326 + if (!enable_locks && _original_lock_fns.alloc == NULL) {
1.327 + /* Case 1: allocate a debug lock. */
1.328 + EVUTIL_ASSERT(lock_ == NULL);
1.329 + return debug_lock_alloc(locktype);
1.330 + } else if (!enable_locks && _original_lock_fns.alloc != NULL) {
1.331 + /* Case 2: wrap the lock in a debug lock. */
1.332 + struct debug_lock *lock;
1.333 + EVUTIL_ASSERT(lock_ != NULL);
1.334 +
1.335 + if (!(locktype & EVTHREAD_LOCKTYPE_RECURSIVE)) {
1.336 + /* We can't wrap it: We need a recursive lock */
1.337 + _original_lock_fns.free(lock_, locktype);
1.338 + return debug_lock_alloc(locktype);
1.339 + }
1.340 + lock = mm_malloc(sizeof(struct debug_lock));
1.341 + if (!lock) {
1.342 + _original_lock_fns.free(lock_, locktype);
1.343 + return NULL;
1.344 + }
1.345 + lock->lock = lock_;
1.346 + lock->locktype = locktype;
1.347 + lock->count = 0;
1.348 + lock->held_by = 0;
1.349 + return lock;
1.350 + } else if (enable_locks && ! _evthread_lock_debugging_enabled) {
1.351 + /* Case 3: allocate a regular lock */
1.352 + EVUTIL_ASSERT(lock_ == NULL);
1.353 + return _evthread_lock_fns.alloc(locktype);
1.354 + } else {
1.355 + /* Case 4: Fill in a debug lock with a real lock */
1.356 + struct debug_lock *lock = lock_;
1.357 + EVUTIL_ASSERT(enable_locks &&
1.358 + _evthread_lock_debugging_enabled);
1.359 + EVUTIL_ASSERT(lock->locktype == locktype);
1.360 + EVUTIL_ASSERT(lock->lock == NULL);
1.361 + lock->lock = _original_lock_fns.alloc(
1.362 + locktype|EVTHREAD_LOCKTYPE_RECURSIVE);
1.363 + if (!lock->lock) {
1.364 + lock->count = -200;
1.365 + mm_free(lock);
1.366 + return NULL;
1.367 + }
1.368 + return lock;
1.369 + }
1.370 +}
1.371 +
1.372 +
1.373 +#ifndef EVTHREAD_EXPOSE_STRUCTS
1.374 +unsigned long
1.375 +_evthreadimpl_get_id()
1.376 +{
1.377 + return _evthread_id_fn ? _evthread_id_fn() : 1;
1.378 +}
1.379 +void *
1.380 +_evthreadimpl_lock_alloc(unsigned locktype)
1.381 +{
1.382 + return _evthread_lock_fns.alloc ?
1.383 + _evthread_lock_fns.alloc(locktype) : NULL;
1.384 +}
1.385 +void
1.386 +_evthreadimpl_lock_free(void *lock, unsigned locktype)
1.387 +{
1.388 + if (_evthread_lock_fns.free)
1.389 + _evthread_lock_fns.free(lock, locktype);
1.390 +}
1.391 +int
1.392 +_evthreadimpl_lock_lock(unsigned mode, void *lock)
1.393 +{
1.394 + if (_evthread_lock_fns.lock)
1.395 + return _evthread_lock_fns.lock(mode, lock);
1.396 + else
1.397 + return 0;
1.398 +}
1.399 +int
1.400 +_evthreadimpl_lock_unlock(unsigned mode, void *lock)
1.401 +{
1.402 + if (_evthread_lock_fns.unlock)
1.403 + return _evthread_lock_fns.unlock(mode, lock);
1.404 + else
1.405 + return 0;
1.406 +}
1.407 +void *
1.408 +_evthreadimpl_cond_alloc(unsigned condtype)
1.409 +{
1.410 + return _evthread_cond_fns.alloc_condition ?
1.411 + _evthread_cond_fns.alloc_condition(condtype) : NULL;
1.412 +}
1.413 +void
1.414 +_evthreadimpl_cond_free(void *cond)
1.415 +{
1.416 + if (_evthread_cond_fns.free_condition)
1.417 + _evthread_cond_fns.free_condition(cond);
1.418 +}
1.419 +int
1.420 +_evthreadimpl_cond_signal(void *cond, int broadcast)
1.421 +{
1.422 + if (_evthread_cond_fns.signal_condition)
1.423 + return _evthread_cond_fns.signal_condition(cond, broadcast);
1.424 + else
1.425 + return 0;
1.426 +}
1.427 +int
1.428 +_evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv)
1.429 +{
1.430 + if (_evthread_cond_fns.wait_condition)
1.431 + return _evthread_cond_fns.wait_condition(cond, lock, tv);
1.432 + else
1.433 + return 0;
1.434 +}
1.435 +int
1.436 +_evthreadimpl_is_lock_debugging_enabled(void)
1.437 +{
1.438 + return _evthread_lock_debugging_enabled;
1.439 +}
1.440 +
1.441 +int
1.442 +_evthreadimpl_locking_enabled(void)
1.443 +{
1.444 + return _evthread_lock_fns.lock != NULL;
1.445 +}
1.446 +#endif
1.447 +
1.448 +#endif
